First look: Behind the scenes of 'Grimm's' Halloween episode

Creepy creatures always abound on "Grimm," but Det. Nick Burkhardt is about to run into something that his family's book of monsters can't help him with on Friday night.

The drama's Halloween episode, titled "La Llorona," is based on the Latin American tale of the same name, which translates to "the weeping woman." In it, a mother, upset that her husband left her for a younger woman, drowns her children before taking her own life, then returns to haunt the living. Nick -- the monster-seeing crime fighter played by David Giuntoli -- makes the connection to the legend when a mysterious being abducts several of Portland's children on Halloween.

That's right. It sounds like in the new episode, Nick won't be up against the various beasts found in Grimm's classic fairy tales, but a ghost instead.

Kate Del Castillo guest stars as Valentina Espinosa, a detective from New Mexico who works with Nick and his partner Hank (Russell Hornsby) to try to solve the child abductions. See what she and the stars of the show had to say about the special episode in this behind-the-scenes look that NBC is sharing with The Clicker:

The "La Llorona" episode airs at 9 p.m. Friday on NBC. In honor of the tale's roots, the episode will also air in Spanish on Telemundo from midnight to 1 a.m. ET Friday night/Saturday morning, and in English from 1 to 2 a.m. Saturday on mun2.